This has been discussed quite a bit in a different thread - I think it's the TWD Owners thread. Do a little looking and you will find it, toward the more recent pages. I think adjusting the switches helped the most.

Yes. It starts on this page then continues on the next page.

https://pinside.com/pinball/forum/topic/twd-club-only-walkers-not-welcome/page/12

Read all the posts made by Eskaybee.

So I don't know if this is related or not but there was a design change to the crossbow mech. If you look in the manual you will see that were was originally a bracket used to keep the coil sleeve in the mech. It was changed last minute as the holes for the mounting screws are still there. Also the plunger is gravity feed. Sometimes the plunger doesn't go back into the mech as there is no spring to help its return. So if the momentum of the ball isn't great enough it wont push the plunger back in. When the crossbow fires there isn't enough umph to shoot the ball out.